Updated 9/1/10

 

            
Introduction:

            
Here are the results
            of two collecting expeditions to a fossil locality in the Late
            Frasnian Devonian Martin Formation north of Payson. This locality
            which was found along Houston Mesa Road at the very top of a
            non descript hill has some of the most unique fauna we have ever
            found in the Martin. Preservation is in a ceramic like white
            chert, and fossils are scattered across a wide area being concentrated
            on the top of the hill due to erosion out of the limestone matrix.
            Found at this unique locality also were large section of crinoid
            stems- totally unlike most Martin localities we have visited,
            urchin spines - extremely rare in this formation, and finally
            hordes of geodes and quartz crystals. Some trace fossils were
            found in one broken block of material, something we dont often
            see in the martin is larger sized burrows. All said, this site
            is a real treasure, one of the sites we will be going back to
            again and again for new exciting finds!


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Coelentrates - Rugose Corals
 
 Solitary
                  Rugose Corals - these range in morphology from barrel shaped
                  at top to like a broad stack of funnels such as the large specimen
                  at the bottom. This one is complete, with root base attachment
                  point still intact. Corals are identified mostly on cross section
                  details by sawing the specimen up into slabs and examining the
                  septal details. Lets just say Im not ready to do this quite yet!
 
 Large
                  magnificent specimen unlike anything we have ever encountered
                  in the Martin.

Echinoids - Urchins
 
 Isolated
                  small spine, some half inch long. Smooth exterior, with ends
                  missing. This would have been from a sea urchin around an inch
                  in diameter.
 
 Another
                  isolated spine, and a crinoid columnal.
 
 Microscopic
                  examination of urchin spine.


Enchinoderms
 
 Large
                  half inch diameter crinoid stems. Many of them were long unbroken
                  pieces up to several inches long. Most crinoid material - IF
                  we find any at all in the Martin - are faint impressions in the
                  limestones. These are amazing.
 
 Interradial
                  Plate, the bottom of the calyx would have been at the top in
                  this orientation. Were looking at crinoids that are golf ball
                  sized on top of long robust stems.
 
 Crinoid
                  armor spike. These circled the calyx and protected the crinoid
                  from large fish and predators.
 
 Collection
                  of stems from the top of the hill, while it was pouring rain.
                  The smaller stems with narrower ridges were nearer to the top.
                  (The stems were tapered)
 
 Microscopic
                  view of stem section. The larger ring in the middle is a nodal,
                  and is where the cirii were attached. these feeler like appendages
                  allowed the crinoid to attach to near by objects and keep their
                  distance from other crinoids.
 
 Microscopic
                  view of armor spike. Think of the crinoids calyx as a mace club
                  with big spikes all over it. Except with crinoids, the spikes
                  were on a band that circled the "equator" of the cup.
                  We find a ton of these in the Naco on a very primitive crinoid
                  type. Perhaps these are an earlier version.?
 
 Microscopic
                  view of interradial plate.
 
 Microscopic
                  view of columnals (ossicles or stem segments). If you split a
                  stem, this is what you get.

Brachiopods
 
 Superb
                  block of limestone with hundreds of brachiopods was a prize find.
 
 Close
                  up of slab shows spirifer and rhynconellids, with some crinoid
                  material.
 
 Cyrtospirifer
                  sp. - Top part of valve exposed, with Cupularostrum sp. to the
                  lower left.
 
 Cupularostrum
                  sp. - a Rhynconellid Brach
 
 Cupularostrum
                  sp. - a Rhynconellid Brach, closer view.


Quartz Crystals and Geodes
 
 Dawn
                  found quite a handful of half inch sized quartz crystals here.
                  Many Martin limestone sites have a few along with the fossils,
                  they seem to grow right in the matrix. The source of the silica
                  for these could very well be the glass sponges that were very
                  common at this time on the sea bottom.
 
 Quartz
                  geode, or "brain stone". These were found in extreme
                  abundance at this site, and range in size from half an inch to
                  about 4 inches. They are psudomorphs, calcedony quartz after
                  some sort of evaporite nodule, maybe Howlite. When these are
                  found, no fossils except trace fossils are found. The sea water
                  was too salty as it evaporated on a shallow flat area.
 
 Inside
                  most geodes are quartz crystals or they are solid white calcedony
                  throughout.
 
 Microscope
                  close up of quartz crystal, a particularly fine one for facets.


Trace Fossils
 
Thallassanoides
                  - Shrimp burrows. The typical "Y" shaped burrows were
                  from a type of callanassid shrimp that occupied tidal flats.
                  Perhaps this is why we found them near the geodes.
 
 The
                  other side of the above specimen.